Oil rags and paper towels= combustion?

The "Oily Rags" fire scenario is associated with non-saturated oils from vegetables & animal fats. For example, linseed oil.

These at normal room temperature & pressure will oxidize, producing heat. If you wrap up a bunch of linseed oil soaked rags tightly, not enough oxygen gets to them to create enough heating to ignite. If you leave them hanging on a clothesline, the heat is dissipated quickly and doesn't build up enough to ignite the rags. Loose packed rags -- loose enough to allow oxygen in, tight enough to insulate is the condition that's most dangerous.

The heat build up will carbonize the paper/cloth, and if the lower ignition temp created by the carbonization matches the temp being made by the oxidization...poof, very rapid oxidization (a fire) starts.

Hydrocarbon oils, like motor oil, are typically saturated and not subject to oxidization or spontaneous heating in normal conditions.

"Yeah, what about the metal shops..."

Well, here we're not talking about the oil (usually petroleum based -- don't use much veggie oil machining AFAIK) oxidizing. But what can oxidize is the fine metal shavings & particles. That produces heat. The heat is vaporizing the petroleum oil. Heat may be carbonizing some paper/rags left with the metal. If the paper ignites, it lights off the oil. Hey cool, we have a fire again! But it's not the oil that caused it, the oil just innocently ignited after the metal oxidization got stuff hot enough.

NG is a celieous(sp) (fiber, cotton, wood, etc;) with carbon and nitrates
No, incorrect, junk science, what ever you want to call it -- that's wrong.

Nitroglycerin is not a cellulose material. It's a liquid. It's "packaged" in a cellulose material for handling -- the cellulose is there for some padding and as something to keep it in. Other wise we'd be walking around with liquid nitro in a bottle which is a might bit more dangerous. Alfred Nobel made a lot of money by figuring out liquid nitro was a lot less dangerous when you packed it in a cellulose material, and he called that combo, "Dynamite."

Here's the chemistry of Nitro:
Link

As for acids and wood, it's theoretical possible. But it's not technically spontaneous combustion. You're adding acid to an organic which generally creates an exothermic reaction. If you put a glass of linseed oil and a glass of concentrated sulphuric acid on the counter, the linseed oil would oxidize and produce heat -- but being disipated by air currents, absorbed by the liquid, and the reduced surface area exposed wouldn't spontaneously ignite. The acid would sit there.

Look at black powder and nitrogylserin (misspelled on perpous) for your answer.

BP is carbon (oil) sulfur and nitrates (acid). A low grade BP is carbon and nitrates. Oil, water and heat makes a acid base thats is in used motor oil and ???

So a rag soaked with used motor oil (carbon) with heavy nitrates (acidic) plus oxygen = combustion

NG is a celieous(sp) (fiber, cotton, wood, etc;) with carbon and nitrates. No oxygen needed as NG makes it's own oxygen and equals combustion of a different type. You probably won't know when you make this one but it will be your last mistake :)

There are some acids that combust upon contact with wood. Although rare it's possible to accidently make this type of acids by mixing common chemicals, so be careful.

You guys also might consider talking brand names via e-mail to keep enquiring minds at rest.

T_Bone

Spontaneous combustion is a very simple process. ANY material that oxidizes is a candidate. The secret to the process is that if the material is left to oxidize where air flow is limited, allowing the build up of heat, it may heat to the point where it self-ignites. This is precisely why rags are often involved.

Drying the contaminated rags in the open air does not allow heat build up to occur. Storing them in an enclosed container deprives them of oxygen. Either way, spontaneous combustion cannot occur under those circumstances.

Your criticism of TBones comments serve no useful purpose. Why not go play somewhere else until you grow up and learn your manners?

As for your link, since when is an insurance company's consumer-focused website (read dumbed down to the lowest common denominator) an even passable source of technical fire information?

Be nice or none of the other children will want to play with you.

Regards, Tip

T_Bone

And>Link then read up on electricity too. You know nothing about either subject.

• Spontaneous Combustion

Pine does not take stain all that evenly or well, so I made several passes and ended up with about a dozen oil-based stain soaked paper towels. In the process of cleaning up, I tossed all the towels into a pile on the (wooden) floor, thinking I'd go right out and get a steel washtub or somewhere else safe to put them.

Then I got distracted, went off to eat dinner, etc. Forgot completely about the pile. About two hours later, I took the household garbage out to the can at the driveway, and noticed a flickering light through the window of the outbuilding. Walked over to check it out, and found a nice "campfire" going on the floor where the pile of paper towels had been, and the whole building full of smoke. I managed to put out the fire and save the building, all the time cursing my idiocy.

I've heard about this problem before, but never experienced it and maybe got a little lax about taking precautions with the oily rags. I can't explain the chemistry that causes such a significant heat rise -- there was nothing more than a pile of oil soaked blue towels on the floor. But I'm a true believer that it can happen -- I've seen it personally.

My dad did the same thing in his garage with the same result. He had a brick garage so no major damage. But yes, it can and does happen.